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Saturday, July 5, 2014

Study MongoDB GridFS with java example

In the past, we have learned basic MongoDB and study data model, in this article , we will study MongoDB GridFS by storing a file into MongoDB. Below is the java simple application to show how to store, retrieve, and delete eventually.

// save into another image imageForOutput.writeTo("/home/jason/Desktop/newsong.mp3");

// delete image gfsMp3.remove(gfsMp3.findOne(newFilename));

}

}

We start by connecting to the server, so with this example MongoDB instance running on server 192.168.0.2 on port 27017. You may want to check the configuration for MongoDB if you connect remotely as the default MongoDB configuration only listen to localhost.

Then we form a MongoDB DB object on mp3db. You can store other object as well but for this example, I'm going to store a mp3. With this ready, we are going to store the mp3. The important piece of code is probably below.

Instantiate two object, GrisFS and GridFSInputFile. You can set additional information like filename, content type. Calling GridFSInputFile.save() will save the object into MongoDB. If you have access to MongoDB cli, command such as > db.mp3.files.find(); will shown below the output.

You can also use GridFS.getFileList(); to retrieve all the files currently store on this database. The code continue on writing the object into a file. As you can see, I'm writing to desktop just to ensure it is not from the source.